A mobile terminal, such as an user equipment (UE), is usually operated with a battery providing the necessary energy to the mobile terminal. Concerning most mobile terminals, it is generally strived for a long standby time, as a long standby time is one key performance of a mobile terminal. During standby, a mobile terminal usually searches for an appropriate cell of a mobile communication network to camp on and associates itself to such a cell that provides comparatively strong radio signal strengths and that thus guarantees a comparatively good quality of a radio connection to the mobile communication network.
In this context, publication D. Fiore et al.: “Cell Reselection Parameter Optimization in UMTS”, 2nd international symposium on wireless communication systems, 2005, IEEE, pages 50-53, describes that user equipment shall regularly search for better cell to camp on according to a cell reselection criterion. Such mechanism shall ensure an acceptable quality of the camping cell. The standby time is decreased by frequent cell reselections, as performing a cell reselection causes some energy consumption. Thus, a very reactive cell reselection mechanism, that is to say: comparatively frequent cell reselections, can guarantee an adequate quality of the camping cell at the expensive of standby time. The publication furthermore describes that a mobile terminal being located in two or more mobile network cells overlapping each other compares signal strength values provided by each of the cells and associates itself to the cell that provides the higher signal strength value. In order to avoid ping-pong effects regarding the cell reselection mechanism due to signal strength values varying in a same small value range, the mobile terminal is equipped with a hysteresis control. Accordingly, the mobile terminal remains associated to a cell, as long as the received-signal strength value of a signal provided by the cell does not leave the hysteresis range. The hysteresis range is defined by a preset value of a difference in received-signal strength between an alternative cell and the currently selected cell. It is also described that increasing the hysteresis range always reduces the reselection rate. This reduction would always lead to an increase of standby time of the mobile terminal but would not necessarily lead to a reduced cell quality.
From EP 1 300 038 a terminal device is known that is configured to select a cell requiring the least amount of energy for transmitting payload data in terms of the radiated power level.